Relationships between Longissimus lumborum muscle characteristics and tenderness of three local beef cattle breeds

Relationships between muscle characteristics (pH, chemical composition, muscle energetic metabolism and contractile types), texture measurements and tenderness of Longissimus lumborum muscle were studied from 242 Aubracs, Gascons and Salers young bulls. There are only low relationships between muscle characteristics and tenderness. About 15 to 26 % of the tenderness variability is related to the variability in muscle characteristics. If some parameters as pH, collagen or protein contents are related to tenderness similarly in the three breeds studied, others characteristics, especially fat content, have relationships with tenderness that depend on the breed. Parameters that explain the highest tenderness variability are also different between breeds. In such a context, it's impossible to predict individual tenderness from these muscle characteristics. For research, data on muscle characteristics can be used to explain sensorial tenderness differences. On the other hand, a muscle characteristic difference doesn't allow to conclude easily about tenderness because of the complexity of biological mechanisms involved. Relationships between texture measurements and tenderness are similar between the three breeds. Shear force is the best predictor of tenderness, it explains up to 48 % of tenderness variability. This result is nevertheless too low for an individual tenderness prediction.